Photographic medium containing an aliphatic amine stabilizer

ABSTRACT

In a photographic medium containing a furfurylidene, an aromatic amine enhancer system and a lower haloalkane sensitizer, the improvement comprising adding an aliphatic amine to the aromatic amine enhancer system.

United States Patent 15 3,637,390 Peterson 1 Jan. 25, 1972 [5PHOTOGRAPHIC MEDIUM [56] Relerences Cited CONTAINING AN ALIPHATIC AMINEUMTED STATES PATENTS STABILIZER 3,394,392 7/1968 Mattor ..96/90 [72]Inventor: John O. H. Peterson, Cape Elizabeth, 3,394,393 7/1968 Mattoret al. 96/90 Maine 3,394,394 7/1968 Mattor et al. ....96/90 AssigneezScott Paper p y, Delaware y, 3,394,395 7/1968 Mattor et al. ..96/90Primary Examiner-Norman G. Torchin [22] Filed; Dec. 19, 1969 AssistantExaminer-Richard E. Fichter A!torneyJohn A. Weygandt, William J. Foley,John W. [21] Appl' 886,738 Kane, Jr. and Martin L. Faigus- 52 us. Cl..96/90, 96/48 ABSTRACT [5 Int. In a p g p medium containing afurfurylidene, an [58] Field of Search ..96/90, 48

matic amine enhancer system and a lower haloalkane sensitizer, theimprovement comprising adding an aliphatic amine to the aromatic amineenhancer system.

7 Claims, No Drawings PIIO'I'OGRAPIIIC MEDIUM CONTAINING AN ALIPHATICAMINE STABILIZER RELATED APPLICATIONS This application is an improvementon the basicprocesses and products described and claimed in U.S. Pat.No. 3,394,395, entitled Photosensitive Medium Comprising aFurfurylidene, A primary Aromatic Amine and A Lower Haloalkane, issuedJuly 23, I968; U.S. Pat. No. 3,394,394, entitled Photographic MediumBased On S-Halo Furfurylidenes," issued July 23, I968; U.S. Pat. No.3,394,392, entitled Photographic Plate Based on Furfurylidene and UsingPolyphenylene Oxide Resin Binder, issued July 23, I968; U.S. Pat. No.3,394,393, entitled Photographic Mediums Based on Furfurylidenes with1-Ch]oro-2,3-Phenylenediamine Enhancer, issued July 23, 1968 andcopending application Ser. No. 746,254, entitled Photographic MediaContaining an Improved Amine Enhancer System, filed July 22, 1968. Thedisclosures and teachings of the aforesaid patents and application arehereby expressly incorporated by reference.

BACKGROUND OF THE INVENTION The parent applications describe aphotographic medium comprised of a furfurylidene derivative, a primaryaromatic amine enhancer and a lower haloalkane sensitizer. The primaryaromatic amine enhancer is described as a primary aromatic aminepreferably containing two primary amino groups, each of which is inresonance with a benzene ring and more preferably, an amine in whichthese amino groups are positioned meta to each other on the same benzenering. The amines are further characterized as having up to two otherfunctional groups on the ring but preferably only one, with a functionalgroup adjacent an amino group. Specific amine compounds include2,6-dich]oro-p-phenylenediamine; 2- chloro-p-phenylenediamine;p-hydroxyaniline; m-phenylenediamine; 4-halo-m-phenylenediamines;4-methoxy-mphenylenediamine; 2,4-toluenediamine;4-ethyl-m-phenylenediamine; benzidine 3,3-dimethoxy benzidine;4-phenoxy-m-phenylenediamine; 4,4'-dianilines; etc., with them-phenylenediamine, mono-substituted-m-phenylenediamines; 2,4-toluenediamine; 4,4-dianilines and benzidines giving the best results.4-Chloro-m-phenylenediamine is one of the preferred amines; producing aphotographic medium which when applied to a flexible substrate has ashelf life at room temperature of about six weeks. Also included in thegroup of primary aromatic amines are mixtures containing at least onemember of the group of primary aromatic amines consisting of morpphenylenediamines, monoor di-substituted mor p-phenylenediamines;aniline, N-phenyl-p-phenylenediamine; 4,4- methylenedianiline;4,4-thiodi-aniline; benzidines or substituted benzidines and at leastone member of the group of polyhalo-substituted phenylenediaminescorresponding to the formula 1 dibromo-p-phenylenediamine or2-chloro-6-bromo-p-phenylenediamine. The 2,6-dibromo-p-phenylenediamineand 2- bromo- 6-chloro-p-phenylenediamine are unique in that they v arethe only compounds which can be employed as a-rnember of eithergrou'p.'Howeve r, as-preyiously stated, they must be employed inconjunction with at least one other member of either group as thedesired increased shelf life, image stability and unique image opticaldensity are not obtained unless employed in such a mixture.

The terms monoor di-substituted mor p-phenylenediamines refer tomonohalo-mor p-phenylenediamines, dichloro-phenylenediamines,mono-halo-monomethyl-phenylenediamines,mono-hal0-monoethyl-.phenylenediamines; methoxy-phenylenediamines,ethoxy-phenylenediamines; 2- bromo-6-chloro-p-phenylenediamine or2,6-dibromo-p-phenylenediamines. The term substituted benzidines" refersto 3,3-dimethoxy or 3,3-diethoxybenzidenes.

Shelf life of a photographic film or medium is very important as longperiods of time often elapse between the production of the film and itsuse. It has been discovered that the photographic media containing aprimary aromatic amine tend to develop irregular areas of discolorationafter about 6 weeks in storage at room temperature in the dark. Theareas of discoloration are believed to be due to the activation of thephotographic medium. Photographic media containing primary aromaticamines become prematurely activated in less than 6 weeks. While the filmbearing the photographic medium that has become prematurely activatedcan be imaged, developed and fixed, the imaging characteristics arealtered unpredictably and the background areas remain permanentlydiscolored. Thus the premature activation of the photographic medium ishighly undesirable. Unique aliphatic amine stabilizers have beendiscovered which when used in combination with the primary aromaticamine enhancers of the previously described systems result inphotographic mediums having lengthened shelf life periods of up to fivefold or greater without discoloration.

It is a further advantage of the present invention that when thephotographic media are prepared utilizing an increased proportion ofpolyphenylene oxide as the resinuous binder, a synergistic effectbetween the polyphenylene oxide binder and the aliphatic/aromatic aminesystem is achieved which gives up to a ten fold increase in shelf lifeof the exposed medium.

The photographic media of the invention produce images which are black,gray or dark brown over the entire exposure range, particularly, whenemploying the m-phenylenediamines described in Ser. No. 746,254. In thepast those enhancers most acceptable in respect to shelf life tended toproduce images more brownish than black. Moreover, the tendency in manycases has been for the image to vary in hue depending upon the degree ofexposure. It has been possible to produce black images in such cases byadding an auxiliary enhancer to the mono-substituted enhancer generallyemployed, but previously used auxiliaries have invariably undesirablyshortened the shelf life of the photographic medium.

Other advantages of the present invention will readily become apparent.

DESCRIPTION OF THE INVENTION The present invention is directed to a newand improved aliphatic/aromatic amine system to be employed in theproduction of photographic media. More particularly, the presentinvention is directed to a new aliphatic/aromatic amine system to beemployed in conjunction with a furfurylidene derivative color former anda lower haloalkane sensitizer.

As previously indicated, the basic photographic medium containingaromatic amine enhancers as previously described in U.S. Pat. Nos.3,394,392; 3,394,393; 3,394,394; 3,394,395 and copending U.S. Pat.application Ser. No. 746,254 is improved by the addition of the uniquealiphatic amine stabilizers of the present invention. The teachings ofthese patents and the copending application arehereby expresslyincorporated by reference.

The photographic medium upon which the present invenderivative as thecolor-forming ingredient, a primary aromatic amine enhancer system and alower haloalkane sensitizer. The photographic medium is negative workingand is usually carried as a film on an impervious flexible support.

In the present specification and claims, the term furfurylidenederivative refers to color-forming furfurylidene compounds andpreferably furfurylidene derivatives corresponding to one of theformulas:

wherein n is 1 or 2, with X, when n is 1, being a hydroxyl amino, phenylor naphthyl radical and when n is 2,. being absent or a phenylene,naphthylene of 4,4'-biphenylene radical; and X is a methyl, nitro orfurfurylidene imine radical or a carbon atom forming a part of a cyclicacetal ring with the other X to give a difurfurylide ne pentaerythritol.

The furfurylidene derivative is prepared in accordance with knownprocedures by reacting furfural with, for example, an amine of polyol.The reaction product is purified, and admixed with a solvent and theother ingredients of the photographic medium to prepare a coatingsolution. The coating solution is applied to a suitable support such ascoated paper and dried to leave the photographic medium in the form of adry film which is photosensitive. A print is made by exposing the filmthrough a photographic negative to light, followed by heating of theexposed film to a temperature greater than 100 C. to develop the image.

Preferably the sensitizer employed in the photograhic mediumis a solidat room temperature having a purity of at least 98 percent withcompounds containing one to two carbon atoms being preferred.Representative preferred compounds are iodoform and pentabromoethane.Iodoform is most preferred. However, carbon tetrabromide andpentabromoethane have been satisfactorily employed.

As employed in the present specification and claims, the

term aliphatic amine refers to menthanediamine, straight and branchedchain aliphatic primary, secondary and tertiary amines containing atleast six carbon atoms, cyclic aliphatic amines, and cyclic aliphaticamines containing two-ring nitrogen atoms. The primary, secondary andtertiary aliphatic amines correspond to the formula wherein R representsa straight or branched chain alkyl moiety containing from three to 24carbon atoms; R independently represents hydrogen or an alkyl groupcontaining from one to 12 carbon atoms and R independently represents Rwith the total number of carbon atoms in R,, R and R adding up to atleast six. Representative cyclic aliphatic amines containing twonitrogens include piperizine. Representative primary, secondary andtertiary aliphatic amines include tributylamine',N,N-dimethylbutylamine; N,N-diethyI-pentylamine; trihexylamine;N-methyl-N-octyldecylamine; dioctylamine; didodecylamine;N-ethyl-N,N-dihexylamine; decylamine; dodecylamine; nonadecylamine;N-rnethylnonadecylamine; N ,N-dimethyl-( 3-propyl-pentadecylamineheptylamine; N,N-diethylhexylamine; trihexylamine; N- ethyloctylamine;N,N-diethyloctylamine; tetracosylamine; N,N-diethyldocosylamine;N-butyl-N-ethylhexylamine; ditertiarybutylamine; triisopropylamine;diisopropylamine; N- hexyl-N(5-ethyloctylamine); cyclohexylamine;N-methylcyclohexylamine; p-dicyclohexylamine; triheptylarnine; N,N-

' didecyloctylam-ine; .N-rnpropyl-N,N-diethylamine; N-methyl-N-pentylamine; N,N-dimethylpentylamine and N-methylhexylamine.

In producing the unique aliphatic/aromatic amine system of the presentinvention the primary aromatic amines or mixtures thereof comprise fromabout 85 to 99.5 percent by weight of the total aliphatic/aromatic aminesystem with the aliphatic amines or mixtures thereof making up thecomplementary portion of the aliphatic/aromatic amine system, i.e., fromabout 0.5 to 15 percent by weight. In general, shelf life of thephotographic medium increases as the proportion of the aliphatic amineincreases up to about 15 percent.

In the preparation of photographic films and other photosensitiveproducts, the furfurylidene color former, the aliphatic/aromatic aminesystem and the haloalkane sensitizer are dissolved in solvent solutionalong with a film-forming plastic polymer to form a coating compositionwhich is applied to a suitable support material. Upon drying, thecoating compositions become photosensitive. Any one of several suitableorganic solvents that are volatile at room temperature or at slightlyelevated temperatures such as chloroform, benezene,l,l,2-trichloro-ethane and methyl-ethyl ketone can be employed as asolvent for the binder and photographic medium. Mixtures of the solventscan be used to obtain improved solvation. The film-forming plasticshould be essentially nonreactive with the other ingredients of thesolution and desirably by itself forms a translucent or transparent filmthat is colorless or substantially colorless so as not to interfere withor mask the color produced by the other ingredients in the photographicmedium. Some polyester polymers have been found to be unsatisfactorypresumably because the hydrogen halide attacks the ester linkage. Thehydrogen halide is believed to be an important intermediate in thechemistry of the dye-formation reactions. Polymers containing largeamounts of hydroxyl groups will usually interfere with image formation.The polymer should be unaffected by anhydrous iodide at F. In most casesit is desirable for the polymer to form a nontacky film. Polymerfilm-formers or binders that are suitable for use in photographic mediaof the present invention include polysulfone, polystyrene andpolyphenylene oxide.

The weight ratio of aliphatic/aromatic amine to the furfurylidene colorformer is usually in the range of 0.1 to 10, preferably 0.5 to 1.5 Theweight ratio of haloalkane sensitizer to color former is in the range of0.1 to 20, preferably 0.5 to 2. The weight ratio of resin to colorformer is not too important. It will usually be in the range of 1 to 40,with the lower ratios below about 5 being preferred from the standpointof intensity and economics. The coating solids used will normally be inthe range of 10 to 20 weight percent.

In order to achieve the synergistic effect when employing the uniquealiphatic/aromatic amine system of the present invention withpolyphenylene oxide resin, the polyphenylene oxide resin is employed ina weight ratio of from 2.5 to 10 with respect to the aliphatic/aromaticamine system. The most marked synergistic effects have been demonstratedusing aliphatic-aromatic amine system comprised of menthane diamine and4-chloro-m-phenylenediamine with the following furfurylidene colorformers being preferred: difurfurylidene pentaerythritol, furfurylidene2-nitro-2-methylpropanediol and difurfurylidene2-amino-2-methylpropanediol.

A photographic plate or film is prepared from the coating solution byapplying it to a suitable support by a conventional means. The coatingweight applied (dry basis) will normally be in the range of 2 to 10pounds per ream (25X38500 sheets) to give a film thickness in the rangeof0.05 to 0.5 mils. The thicker the film, the more intense the image;however, if

the film is too thick, it is difficult to fix the background. The

film thickness desired will be dependent upon the vapor pressures of theamines employed and the particular resin employed.

The support used in the preparation of a photographic product can have asuitable coated surface to withstand the penetration of organicsolvents. In the case of paper;-starch,

potassium polyacrylate resins, polyvinyl alcohol, and similar bindersare employed to produce the barrier coat. In general, film-formingwater-soluble resins can also be employed to produce the barrier coat;however, casein and other proteinaceous resins have been found to bedetrimental to the photographic medium when said resins are employed inthe barrier coat. In the case of transparent supports, films ofpolyethylene terephthalate resin (DuPonts Mylar) have proved to beexcellent supports and particularly suitable for the preparation offilms of microphotographic copying. Materials such as cellophane are notusable except under special conditions because of the plasticizerpresent. Uncoated thin paper sheets, such as a carbonizing paper, canalso be impregnated with the solutions to give a translucent appearingproduct or sheet.

EXAMPLES The following examples illustrate the desirable photographiccharacteristics exhibited by photographic media containing the amineenhancer system of the present invention: (These examples are merelyillustrative and are not deemed to be limiting).

EXAMPLE 1 A web of bleached paper bodystock having a basis weight of 45pounds per ream (25X38-500) was base coated with 15 pounds per ream of acoating composition containing, by dry weight, 12 parts of ammonia-cutcasein, 14 parts of precipitated calcium carbonate, 86 parts of a No. 1quality domestic paper-coating clay, 8 parts of a styrene-butadienelatex, one-half part of tetrasodiumpyrophosphate as a dispersant, andone-half part of potassium oleate as a release agent, with sufficientwater to bring the total solids to 50 percent.

This coating composition was applied to one side of a web of theabove-described bodystock by means of an air knife coater, and dried byconventional means.

The resultant coated paper had a basis weight of 60 pounds per ream. Toprovide a continuous film for proper solvent holdup an intermediatecoating composition was prepared, comprised of 25 parts (wet weight) ofan aqueous solution containing 25 percent by weight ofa polyvinylalcohol (Vino! 125 sold by Air Reduction Company), 75 parts of a 50percent slurry of titanium dioxide (DuPonts RA 50), 1 part of a wettingagent comprised of a premixed combination of 0.5 part of Tergitol NPXand 0.5 part of tributylphosphate and sufiicient water to make a20-percent solids coating composition. Four pounds per ream, dry weight,of this coating composition was applied by means of an air knife coaterto the base-coated web. This coating was finished in sequence byconventional supercalendering.

The photographically desirable coated surface thus obtained wastopcoated with a photographically sensitive coating composition by meansofa No. 20 Mayer bar. The sequence in which dry components are added isnot critical in preparing the coatings of the present invention. In aconvenient procedure, the top-coating composition was prepared bycombining, by dry weight, 1.0 part difurfurylidene pentaerythritol, 0.5part 4-chlor0-m-phenylenediamine, 0.025 part menthanediamine and1.0-part iodoforrn.

To these dry components were added as a binder 60 parts (wet weight)polyphenylene oxide resin (General Electrics PPO) which was dissolved ina percent chloroform solution. The entire mixture was stirred until anhomogenous composition was obtained.

This coating composition was applied to the coated substrate hereindescribed by No. 20 Mayer bar in an amount equal to 5 pounds per reamdry weight.

After drying, the photographically sensitive sheet thus obtained wasexposed through a negative transparency using a 7.5 KVA carbon arc lampat 24 inches for 60 seconds. Development was effected by heating at 370F. for 30 seconds.

The positive image thus produced exhibited a high optical density (Dmaxof 2.0) in the image areas inverse to the colorless areas of thenegative employed for exposure. Sharp, clearly defined contrast wasexhibited between the nearly black image areas and the white backgroundareas.

In a further operation conducted as described in example 1, coatingcompositions were prepared wherein furfurylidene- 2nitro--2-propanedioland 3-difurfurylidene-2-amino-2- methylpropanediol were substituted fordifurfurylidene pentaerythritol as the sole color former and all othercomponents were unchanged. A clear positive image having high contrastand excellent optical density was obtained when sheets bearing thiscoating were exposed to a negative and developed. The photographic mediathus prepared showed shelf lives of 20 days when stored at F. in thedark. Other photographic media similar in all respects except that thecoatings contain no aliphatic amine exhibited shelf life of only threedays under the same test conditions. 1

EXAMPLE 2 In further operations, base sheets were prepared exactly asdescribed in example 1 and coated with a photographic top coatingcomprising 400-parts difurfurylidene pentaerythritol, 400-partsiodoform, 300-parts 4-chloro-m-pheny1enediamine and either SO-partstert.-octylamine 50 parts N ,N-dimethyldodecylamine or SO-partspiperizine as the sole aliphatic amine constituent of thealiphatic/aromatic amine system.

Each of these dry component systems was added to a binder systemcomprised of 800 parts by dry weight of polyphenylene oxide resin (PPOsold by General Electric Company) and dissolved in chloroform to make al4-percent solution. Each mixture was stirred until an homogenouscomposition was obtained and each mixture separately coated as describedin example l in an amount equivalent to 5 pounds per ream.

After drying the photographically sensitive sheet obtained was exposedand developed as described in example 1 to obtain a high optical densityimage. Sharp, clearly defined contrast was exhibited between the nearlyblack image areas and the white background areas.

Other sheets of the coated but unexposed and undeveloped photographicelements were heated at 100 F. in the dark for a period of 10 days. Atthe end ofthis time, no discoloration was observed.

In further operations, a photographic medium was prepared substantiallyas described in the preceding portion of example 2 with the onlydifference being that a mixture of 100 parts of m-phenylenediamine and300 parts of 4-chloro-m-phenylenediamine is employed in place of the4-chloro-m-phenylenediamine. The medium thus prepared is coated asdescribed above in this example and shown to be stable to heat by thetest methods described above.

EXAMPLE 3 In further operations, photographic media A, B and C havingthe composition set forth in table 1 were prepared and coated on thebase stock described in example 1 using the methods of example 1. Afterthe photographic elements were prepared and dried they were placed in anoven at 100 F. for 30 days. At the end of this period, the photographicelements were removed and no discoloration was observed.

EXAMPLE 4 In another illustration of the sharp photographic contrastwhich may be obtained by employment of the stabilizer systems of thepresent invention, a conventionally coated and supercalendered basesheet was employed. This paper web was of bleached bodystock having abasis weight of 57 pounds per 25 38500 sheet ream. Upon both surfaces ofthis web a pigmented surface size containing sufficient water to make acomposition of 25 percent solidshad been applied by asize press in anamount equal to 3 pounds per ream per side. After drying, a secondcoating comprised by dry weight of 100 parts No. 1 domestic coating claywith IO-parts starch and S-parts styrene-butadiene latex as a binder wasmixed with sufficient water to obtain 60-percent solids and was appliedto one surface of the previously coated web in an amount equal to 7pounds per ream.

The thus coated web having a basis weight of 70 No. ream was dried byconventional means and supercalendered through five nips at 1,500 pli.The web thus obtained was smooth enough to be desirable for photographicquality detailed image reception.

An intermediate, continuous-film coating composition as described inexample 1 was applied in an amount equal to 4 No. ream.

The thus coated web was topcoated by means of a No. Mayer bar with 4pounds per ream of a photographically sensitive coating. This coatingwas comprised of 1.0-part difurfurylidene pentaerythritol, 0.2-part4-chloro-m-phenylenediamine, 0.8-part dibromo-toluenediamine, 0.15-partdin-propylamine and LS-part iodoform. As in example 1, these componentswere mixed under vigorous agitation with 60 parts (wet weight) of aIO-percent solution of polyphenylene oxide in chloroform.

After drying of the coated sheet, exposure was accomplished by themethod of example 1. Development was by heating at 350 F. for 40seconds.

The positive images produced upon this surface were of high opticaldensity in those areas inverse to the colorless portions of the negativeoriginal and exhibited excellent contrast between the near-black of theimage areas and the white, unyellowed background areas.

The preparation of the aliphatic amine compounds is well known in theart and the primary aromatic amine compounds are known in the art andtheir preparation described in the patents and application herebyincorporated by reference.

I claim:

1. in a photographic plate comprising, on a support, a layer of aresinous binder containing a furfurylidene derivative color-former, aprimary aromatic amine enhancer system and a lower haloalkanesensitizer, the improvement comprising the addition of one or morealiphatic amines taken from the group consisting of menthanediamine,primary, secondary or tertiary aliphatic amines containing at least sixcarbon atoms, cyclic aliphatic amines and cyclic aliphatic aminescontaining two ring nitrogen atoms, the aliphatic amine contentcomprising 0.5 to 15 percent by weight of the total amine content, theresinuous binder being employed in a weight ratio of from 2.5 to 10 withrespect to the total amine content, the weight ratio of the total aminecontent to the color-former being in the range of 0.1 to 10, the weightratio of haloalkane sensitizer to color-former being in the range of 0.1to 20 and the weight ratio of resinous binder to color-former being inthe range of l to 40.

2. The photographic plate claimed in claim 1 wherein the furfurylidenederivative is difurfurylidene pentaerythritol.

3. The photographic plate according to claim Iwherein the resinousbinder is polyphenylene oxide, polysulfone or polystyrene.

4. The photographic plate claimed in claim 3 wherein the resinous binderis polyphenylene oxide, the primary aromatic amine is4-chloro-m-phenylenediamine and the aliphatic amine is menthanediamine.

5. The photographic plate claimed in claim 1 wherein the primaryaromatic amine is 4-chloro-m-phenylenediaminc and the aliphatic amine istaken from the group consisting of tert.- octylamine,N,N-dimethyldodecylamine, piperizine and di-npropylamine.

6. The photographic plate claimed in claim wherein the primary aromaticamine is 4-chloro-m-phenylenediamine and the aliphatic amine ismenthanediamine.

7. The photographic plate claimed in claim 1 wherein the primaryaromatic amine enhancer is a mixture of 4-chloro-mphenylenediamine andm-phenylenediamine and the aliphatic amine is menthanediamine.

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3637 390 Dated January 25, 1972 lnv n fl John 0. 1-1. Peterson It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 5, line 46. chanqe "0.5" to 15 Column 7, line 5, change"stabilizer" to enhancer -line 20, change "No." to pounds per and line27, change "N09" to pounds per Column 8, line 37, after "claim" insert lSigned and sealed this 26th day of December 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents em I J

2. The photographic plate claimed in claim 1 wherein the furfurylidenederivative is difurfurylidene pentaerythritol.
 3. The photographic plateaccording to claim 1 wherein the resinous binder is polyphenylene oxide,polysulfone or polystyrene.
 4. The photographic plate claimed in claim 3wherein the resinous binder is polyphenylene oxide, the primary aromaticamine is 4-chloro-m-phenylenediamine and the aliphatic amine ismenthanediamine.
 5. The photographic plate claimed in claim 1 whereinthe primary aromatic amine is 4-chloro-m-phenylenediamine and thealiphatic amine is taken from the group consisting of tert.-octylamine,N, N-dimethyldodecylamine, piperizine and di-n-propylamine.
 6. Thephotographic plate claimed in claim 1 wherein the primary aromatic amineis 4-chloro-m-phenylenediamine and the aliphatic amine ismenthanediamine.
 7. The photographic plate claimed in claim 1 whereinthe primary aromatic amine enhancer is a mixture of4-chloro-m-phenylenediamine and m-phenylenediamine and the aliphaticamine is menthanediamine.